(25 days)
The dS Small Extremity 16Ch 1.5T Coil is to be used in conjunction with a Philips 1.5T Magnetic Resonance Scanner to produce diagnostic images of the extremities that can be interpreted by a trained physician.
The proposed dS Small Extremity 16Ch 1.5T Coil is designed for use with Magnetic Resonance Imaging (MRI) systems. The coil is designed to work in unison with the Body Coil of the MRI system, which will transmit the radio frequency (RF) signals, so that the coil may receive the resultant RF signal from the excited nuclei.
The proposed dS Small Extremity 16Ch 1.5T Coil is a volume phased array receive-only coil for high resolution diagnostic imaging of small extremities. The coil is made of two flexible flaps and adjustable straps for ease of workflow. The coil rigid housing is made with Lexan 925 material and the foamed pad is coated with Dartex Polyurethane; with dimensions to be 13.5"x10x9 inches to accommodate 16 Channel construction; the former using Kapton rigid-Flex PCB (loop elements) and FR-4 PCB (feedboard, interface boards), and urethane-jacketed cable to connect to MR system. The coil provides unilateral images (Left and Right) of the anatomy of interest.
The small extremity (Hand, Finger, Elbow) comfort pads are made of Urethane core with Polyvinyl Nitrile wrap, coated with Polyscan material; the Base Plate and Table Pads are also coated with Polyscan material.
The provided document describes the safety and performance testing for the dS Small Extremity 16Ch 1.5T Coil, focusing on non-clinical performance and a clinical demonstration rather than a comparative effectiveness study with human readers or a standalone algorithm study.
Here's an analysis of the acceptance criteria and the study that proves the device meets them:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Specific Acceptance Criteria | Reported Device Performance |
|---|---|---|
| Non-Clinical Testing | Compliance with Standards: | |
| - IEC 60601-1, 3rd edition (Medical electrical equipment - Part 1: General requirements for basic safety and essential performance) | Complies | |
| - IEC 60601-2-33, 3rd edition (Medical electrical equipment - Part 2-33: Particular requirements for the basic safety and essential performance of magnetic resonance equipment for medical diagnosis) | Complies | |
| - ISO 14971, 2nd edition (Medical devices - Application of risk management to medical devices) | Complies (Risk Management ensured via Invivo Risk Management procedure) | |
| - ISO 10993-1, 2nd edition (Biological evaluation of medical devices - Part 1: Evaluation and testing within a risk management process) | Complies | |
| - Device specific draft guidance document, "Submission of Premarket Notifications for Magnetic Resonance Diagnostic Devices - July 14, 2015" | Complies | |
| Coil Decoupling: | Achieved through a redundant decoupling strategy using PIN diodes across a capacitor tuned to shift resonant frequency, and a fuse for current events; passive decoupling if unplugged. | |
| Electrical Isolation: | Electrical conductors encased in plastic housing (minimum 0.10" thick wall/foam); cables designed to prevent looping and separate from patient. | |
| Signal-to-Noise Ratio (SNR) Characterization | Characterized, but specific quantitative acceptance criteria or values are not provided in the summary. | |
| Image Uniformity Characterization | Characterized, but specific quantitative acceptance criteria or values are not provided in the summary. | |
| Special Purpose of RF Receive-Only Coil Characterization | Characterized, but specific quantitative acceptance criteria or values are not provided in the summary. | |
| Clinical Demonstration | Image Quality Adequacy: Diagnostic images of the extremities (Hand, Finger, Elbow) interpreted by a trained physician to confirm adequate image quality. | Clinical radiologist reviewed DICOM images from the clinical demonstration and confirmed the image quality is adequate. (Supporting attestation statements provided in Appendix 5, Clinical Evaluation). |
| Overall Equivalence | Substantial Equivalence: Device is as safe, as effective, and performs as well as or better than the predicate device (1.5T and 3.0T-8Channel Small Extremity Coil, K091902) in terms of design features, principles of operation, technological characteristics, indications for use, and safety and effectiveness. | Demonstrated through non-clinical performance (verification and validation) tests, compliance with specifications and standards, and the clinical demonstration. |
2. Sample size used for the test set and the data provenance
- Test Set Sample Size: The document does not specify a numerical sample size for the "clinical demonstration". It mentions "representative anatomic region (extremity imaging)" but doesn't quantify the number of patients or images.
- Data Provenance: Not explicitly stated regarding country of origin. The study is referred to as a "clinical demonstration" and involves image review, suggesting it is akin to a retrospective review of prospectively acquired demonstration images, rather than a full prospective clinical trial.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts
- Number of Experts: One clinical radiologist was used.
- Qualifications: "a clinical radiologist." No further details on years of experience or specialization are provided in this summary.
4. Adjudication method for the test set
- Adjudication Method: Not applicable in the traditional sense of multiple readers and a dispute resolution process. A single clinical radiologist reviewed the images and provided an attestation of adequate image quality.
5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance
- No MRMC Comparative Effectiveness Study was done. This submission is for an MRI coil, a hardware component, not an AI-powered diagnostic algorithm. Therefore, the concept of human readers improving with or without AI assistance is not relevant to this device's evaluation.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
- No Standalone Algorithm Performance Study was done. This device is an MRI coil, which is a hardware component that produces images for human interpretation, not a standalone algorithm.
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
- For the clinical demonstration, the ground truth for "adequate image quality" was based on the assessment/attestation of a single clinical radiologist. This is a form of expert opinion/assessment rather than a definitive "ground truth" like pathology. For the non-clinical tests, the ground truth was based on compliance with established engineering specifications and international/FDA-recognized consensus standards.
8. The sample size for the training set
- Not Applicable. This is a hardware device (MRI coil), not an AI algorithm. Therefore, there is no "training set" in the context of machine learning.
9. How the ground truth for the training set was established
- Not Applicable. As there is no training set for an AI algorithm.
§ 892.1000 Magnetic resonance diagnostic device.
(a)
Identification. A magnetic resonance diagnostic device is intended for general diagnostic use to present images which reflect the spatial distribution and/or magnetic resonance spectra which reflect frequency and distribution of nuclei exhibiting nuclear magnetic resonance. Other physical parameters derived from the images and/or spectra may also be produced. The device includes hydrogen-1 (proton) imaging, sodium-23 imaging, hydrogen-1 spectroscopy, phosphorus-31 spectroscopy, and chemical shift imaging (preserving simultaneous frequency and spatial information).(b)
Classification. Class II (special controls). A magnetic resonance imaging disposable kit intended for use with a magnetic resonance diagnostic device only is exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 892.9.